Production of malonic anhydrides and derivatives thereof

Abstract

Malonic anhydride and substituted malonic anhydrides are prepared by ozonolysis of the enol-lactone dimers of ketenes. The resulting malonic anhydrides can be hydrolyzed with water to form the corresponding acid, reacted with an alcohol to yield the monoester, or reacted with an amine to yield the monoamide.

What is claimed is: 
     
       1. A process for producing malonic anhydride and substituted malonic anhydrides, which comprises subjecting an enol-lactone dimer of a ketene to ozonolysis in an inert solvent, said enol-lactone dimer of a ketene having the general formula ##STR3## where R and R' are selected from the group consisting of hydrogen, alkyl, cycloalkyl, a heterocyclic group selected from the class consisting of pyridyl, tetrahydropyranyl and tetrahydrofuryl, aryl, and where R and R' can be the same or different, and where R and R' together can constitute the atoms necessary to form a carbocyclic ring, the temperature of the reaction mixture being maintained below about 0° C., and forming a malonic anhydride. 
     
     
       2. The process as defined in claim 1, the temperature of the reaction mixture being maintained at between about -100° C. and -50° C. 
     
     
       3. The process as defined in claim 1, said ozonolysis being carried out by passing a stream of ozone through said solvent. 
     
     
       4. The process as defined in claim 3, employing an amount of ozone sufficient to convert substantially all of said dimer of a ketene to said malonic anhydride. 
     
     
       5. The process as defined in claim 3, wherein said ketene dimer is diketene and the anhydride formed is malonic anhydride. 
     
     
       6. The process as defined in claim 3, wherein said ketene dimer is 3-hydroxy-2,2,4-trimethyl-3-pentenoic acid β-lactone, and the anhydride formed is dimethylmalonic anhydride. 
     
     
       7. The process as defined in claim 1, said ozonolysis being carried out in an inert organic solvent containing said enol-lactone dimer of a ketene, by passing a stream of ozone through said solvent. 
     
     
       8. The process as defined in claim 5, the temperature of the reaction mixture being maintained in the range from about -100° C. to below about 0° C. 
     
     
       9. The process as defined in claim 6, the temperature of the reaction mixture being maintained in the range from about -100° C. to below about 0° C.